Minimal Phototoxic Dose for Vitiliginous Skin Lesions

Kim, Hyup; Park, Jang Kyu; Seo, Young Joon; Lee, Jeung Hoon

Abstract

BACKGROUND
Photochemotherapy (PUVA) is the effective treatment for vitiligo. It is necessary to measure the minimal phototoxic dose (MPD) in order to ascertain a safe, effective UVA dose needed for irradiation during photochemotherapy. OBJECTIVE: The purpose of this study was to standardize the MPD for vitiliginous lesions. METHOD: The MPD was measured in 124 vitiligo patients. The number of patients monitored for topical and systemic MPD using the photosensitiser, 8-methoxypsoralen (8-MOP) were 41 and 83, respectively. MPD was also analysed according to sex, age, site of the vitiliginous lesions, duration of disease, season and administration route of the photosensitiser.
RESULTS
1. In the group assessed for topical application of 8-MOP cream, mean MPD was 0.62+/-0.59J/cm2. 2. In the group assessed for systemic administration of 8-MOP, mean MPD was 2.68+/-1.83J/cm2. 3. MPD in the group systemically administrated with 8-MOP was 4.32-fold to that of the topical application group (p<0.01). 4. In the case of both topical and systemic administration of the photosensitiser, 8-MOP, no significant differences in MPD were found due to the sex, age, site of vitiliginous lesions, duration of disease, or season in which MPD was administered to patients. CONCLUSION: There was a significant difference in MPD between the topical application group and the systemic administration group.